This invention concerns instruments for setting posts or beams so as to be both plumb or level and at a predetermined height relationship with other posts or beams being set.
There has heretofore been developed angled side instruments having a bubble level mounted on each side of the angled side instrument, the instrument adapted to be held against two sides of a round or square post such as a 4.times.4 or 6.times.6. The post is thus able to be set plumb by centering the bubble of each level extending in two orthogonal directions to set the plane of the top of the post horizontal.
It often is required to set the height of a number of posts relative each other, as when constructing a post supported deck. This must be done by using other devices or techniques, as by leveling a long piece of lumber between the posts. Line levels are also sometimes used. These techniques are slow and inaccurate.
There has also long been used water level devices in which a water filled flexible hose connects two sight tubes, the level of water in each tube being the same to enable height comparison of two widely separated posts or other structural member.
See U.S. Pat. No. 4,991,302 issued on Feb. 12, 1991, for an "Open Circuit Levelling Measuring System" and U.S. Pat. No. 4,686,773 issued on Aug. 18, 1987 for a "Structure Leveling System" for examples of these systems.
Use of these devices require a separate set up, also slowing completion of the project.
While water level devices have sometimes been provided with bubble levels, these have been only used to plumb the tubes. See U.S Pat. No. 4,231,163 issued on Nov. 4, 1980, for a "Level Indication and Elevation Indicating Device" and U.S. Pat. No. 318,885 issued on May 26, 1885 for a "Device for Leveling Aligning Shafts".
It is the object of the present invention to provide instruments which conveniently enable establishing both plumb or level, and a predetermined height relationship between posts, or a level or predetermined slope and relative height of horizontally extending structural members such as beams.